Diagnostic instrument



FIG. 1 is a front, right side perspective view of a diagnostic instrument, showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a front and right side perspective view thereof showing a test strip receptacle extending from the front thereof. 

The ornamental design for a diagnostic instrument, as shown and described. 